v1.3.1 to add waitingForDRD()

### Releases v1.3.1

1. Add waitingForDRD() function to signal in DRD wating period. Check [DRD is waiting for a double reset? #14](#14)
2. Add example [checkWaitingDRD](https://github.com/khoih-prog/ESP_DoubleResetDetector/tree/master/examples/checkWaitingDRD) to demo how to use the new feature.

Author: khoih-prog

examples/ConfigOnDoubleReset/ConfigOnDoubleReset.ino

@@ -309,7 +309,7 @@ IPAddress APStaticSN  = IPAddress(255, 255, 255, 0);
 #include <ESP_WiFiManager.h>              //https://github.com/khoih-prog/ESP_WiFiManager
 
 // Function Prototypes
-uint8_t connectMultiWiFi(void);
+uint8_t connectMultiWiFi();
 
 ///////////////////////////////////////////
 // New in v1.4.0
@@ -444,7 +444,7 @@ uint8_t connectMultiWiFi()
   return status;
 }
 
-void heartBeatPrint(void)
+void heartBeatPrint()
 {
   static int num = 1;
 
@@ -464,7 +464,7 @@ void heartBeatPrint(void)
   }
 }
 
-void check_WiFi(void)
+void check_WiFi()
 {
   if ( (WiFi.status() != WL_CONNECTED) )
   {
@@ -473,7 +473,7 @@ void check_WiFi(void)
   }
 }
 
-void check_status(void)
+void check_status()
 {
   static ulong checkstatus_timeout  = 0;
   static ulong checkwifi_timeout    = 0;

examples/checkWaitingDRD/checkWaitingDRD.ino

@@ -0,0 +1,132 @@
+/****************************************************************************************************************************
+   checkWaitingDRD.ino
+   For ESP8266 / ESP32 boards
+
+   ESP_DoubleResetDetector is a library for the ESP8266/Arduino platform
+   to enable trigger configure mode by resetting ESP32 / ESP8266 twice.
+
+   Based on and modified from DataCute https://github.com/datacute/DoubleResetDetector
+
+   Built by Khoi Hoang https://github.com/khoih-prog/ESP_DoubleResetDetector
+   Licensed under MIT license
+ *****************************************************************************************************************************/
+
+// These defines must be put before #include <ESP_DoubleResetDetector.h>
+// to select where to store DoubleResetDetector's variable.
+// For ESP32, You must select one to be true (EEPROM or SPIFFS)
+// For ESP8266, You must select one to be true (RTC, EEPROM, LITTLEFS or SPIFFS)
+// Otherwise, library will use default EEPROM storage
+
+// This example demonstrate how to use new function waitingForDRD() to signal the stage of DRD
+// waitingForDRD() returns true if in DRD_TIMEOUT, false when out of DRD_TIMEOUT
+// In this example, LED_BUILTIN will blink in DRD_TIMEOUT period, ON when DR has been detected, OFF otherwise
+
+#ifdef ESP8266
+  #define ESP8266_DRD_USE_RTC     false   //true
+#endif
+
+#define ESP_DRD_USE_LITTLEFS    true
+#define ESP_DRD_USE_SPIFFS      false
+#define ESP_DRD_USE_EEPROM      false
+
+// Uncomment to have debug
+//#define DOUBLERESETDETECTOR_DEBUG       true
+
+#include <ESP_DoubleResetDetector.h>      //https://github.com/khoih-prog/ESP_DoubleResetDetector
+
+// Number of seconds after reset during which a 
+// subsequent reset will be considered a double reset.
+#define DRD_TIMEOUT 10
+
+// RTC Memory Address for the DoubleResetDetector to use
+#define DRD_ADDRESS 0
+
+DoubleResetDetector* drd;
+
+#ifdef ESP32
+
+  // For ESP32
+  #ifndef LED_BUILTIN
+    #define LED_BUILTIN       2         // Pin D2 mapped to pin GPIO2/ADC12 of ESP32, control on-board LED
+  #endif
+
+  #define LED_OFF     LOW
+  #define LED_ON      HIGH
+
+#else
+
+  // For ESP8266
+  #define LED_ON      LOW
+  #define LED_OFF     HIGH
+
+#endif
+
+bool DRD_Detected = false;
+
+void check_status()
+{
+  static ulong checkstatus_timeout  = 0;
+  static bool LEDState = LED_OFF;
+
+  static ulong current_millis;
+
+#define DRD_CHECK_INTERVAL    500L
+
+  current_millis = millis();
+
+  // If DRD_Detected, don't need to blink, just keep LED_BUILTIN ON
+  if ( !DRD_Detected && ((current_millis > checkstatus_timeout) || (checkstatus_timeout == 0)) )
+  {
+    // If in DRD checking loop, blinking the LED_BUILTIN
+    if ( drd->waitingForDRD() )
+    {
+      digitalWrite(LED_BUILTIN, LEDState);
+
+      LEDState = !LEDState;    
+    }
+    else
+    {
+      digitalWrite(LED_BUILTIN, LED_OFF);
+    }
+    
+    checkstatus_timeout = current_millis + DRD_CHECK_INTERVAL;
+  }
+}
+
+void setup()
+{
+  pinMode(LED_BUILTIN, OUTPUT);
+  
+  Serial.begin(115200);
+  while (!Serial);
+
+  delay(200);
+
+  Serial.print("\nStarting checkWaitingDRD on"); Serial.println(ARDUINO_BOARD);
+  Serial.println(ESP_DOUBLE_RESET_DETECTOR_VERSION);
+   
+  drd = new DoubleResetDetector(DRD_TIMEOUT, DRD_ADDRESS);
+
+  if (drd->detectDoubleReset()) 
+  {
+    Serial.println("Double Reset Detected");
+    digitalWrite(LED_BUILTIN, LED_ON);
+    DRD_Detected = true;
+  } 
+  else 
+  {
+    Serial.println("No Double Reset Detected");
+    digitalWrite(LED_BUILTIN, LED_OFF);
+  }
+}
+
+void loop()
+{
+  // Call the double reset detector loop method every so often,
+  // so that it can recognise when the timeout expires.
+  // You can also call drd.stop() when you wish to no longer
+  // consider the next reset as a double reset.
+  drd->loop();
+
+  check_status();
+}